Asphalt blending



Dec. 6, 1960 J. M. M DONALD ASPHALT BLENDiNG.

Filed Aug. 28. 1956 BLEND/I16 ruvx Asphalt ASP/MIT Di/uenf mmvron.

Ja/m M MacDonald ATTORNEY invention ana refuge trad gor "very" viaus hydr ocarbonaceous als jfand low viscosity hydro-1 c'arbon'oilsi Particularly'therinvention relates to the preparation of 'cut back 'iasphalt s. k

A common 'probl'e'rnto t mak f tw ere: h l' e d we the moreradily coafth e si lffab' o fa gr gate with subsequent vaporizing the diluent oil, leaving only the asphaltic material to do the actual binding The blendin'gfiof'avery viscbus material-" as an asphalt ora'residuum withafldw be g hy ro ca'rb'on isf not'a'simple task. Simply dumping thet o material s into a tank and 'circulatih'g the-contents by pump're'quire's" frequently hours' of circulation Thefinore 'u'spal mama" involves heating' thefviscous 'rn'aterial to a tein'perature at" Which'it iSfairlyfilfid; adding thf 10W "boiling; 10W vi's-f cosity hydrocarbon to thetankandtheii agitatin'gytlie contents'with air until a 'm'ate'rial of'sub" antially" uniform viscosity throughbufthetank' is obtain (A criterjion of good blending is the subst al'itiall'y' samefvis eosityjof samples taken I fromdifferent portions of thhankfafterf agitation of i the "cont'entsfy In view of th'e higherfter ri peratures involved and the presence of tree okyg en, a real fire hazard"exists"during siiehan airblo'wing operation.

An" object of the inventibn is th"bl ridirigf ot a lid or semi-solid hydrocarbohaceiis material and alow" viscosity hydrocarbofoikin' a simple"and safe manner. Another 'obj'ect is a simple and sa'f procedure fqrpr ration of cut back asphalts. Other objects iwill become apparent in the coarse -or 'the penned description of the invention. V The blending method of the instant invention? coin prises introducing a materialselec'ted :frorfi'the' CIaS Sj'COnY- sisting of semi-solid arifd'fsolid hydrocarbonaceous rna terials at a temperature such 'thatthe Saybolt Fur-o1 YiSj cosity of said m'at'erialf-is not we ma e- 5 m r3000; seconds, said temperature bein'g between about 150 F. andabout 350 F. into a ta'rik "provided" Withdistributor means positioned substanfiallyatthe bc'attom of s aidftaink, 7 said distributor "means beiiig pfbvided with ja "m'ult ipheity f of "substantially uniformly spaced" orifices, said! orifices being between'abdu't A" andfj /g inch in diamete an bein pos itiohed-"so that fluiddeavin sfid orifices is di-"' rected up w ard substantially perpendicularly to the bot-j tom of said tank, and introducing'thr'ough said distributor meansajlow viscosity hydrocarbon oil at a rate'such' th'atjfby theftirn'eall of said'hydrocarbon oil has been introduceijthe entire'contents of said tank are subst'an-.

tiall'y funiforinly intermingled.

Thehydrocarbonaeeo'us"material of' high viscosity which.

isftd"beireducedin'viscosity by adm'iirture'with a low viscosity hydroearbonoil is a s'mi solid or solid hydrocarbonaceous material such as a petroleum residuum (residualc'r'ude),residu'alasphalt, cracked tar, or blown asphalt." Inaddition; to these products from the dis: tiljla'ti'on of 'crjlide oil or" hydrocarbon conversion operationsflhje methodoffthe invention is applicable to native asphalts" andasph'altite's. It is to" be understood tha t the;

terminologywith respect to'these highviscosity materials conformsftdthat of Abraham; Asphalt s and Allied Subta ces to'ariy ydrocafbo'naceous material which has a'viscosity scale of nor'more than seconds atf'atemperature not in excess of FL 350""F. is "genrally con sidered as about; at which'cut back asphalts the maximum" temperature can be prepared."

I Th operating temp'era'turesin'generakrange between a fut lfdij F. and 350 F., the temperature being admaterlal does not: exceed about 3000 VISCOUS a th base; in generalnif is' preferred to; use' a temperature between about 175 F.' and250 V'Ilh eilovv'viscosity hydrocarbon oil' utili zed in the met odfhreinhnayj be any, one of the oils lcommonly' usdinthepreparation of cut back asphalts or in reducingtheyiscosity of very viscous hydrocarbon oils. In ge" he diluent'is a petroleum product boiling in the rng'e b tWefiabbl Jt 250 91 and 7009 The diluent,

i.e"1'oil "boiling" overthe range of about 250 F. to 450 eitheifvirgin; thermally -cracked, or catalyticallyj cracked,

i.'e.", an oilboilingover'therange of about 350 F. and",

550KB. or avheavyI'gas'oil which boils from about 500 F. toTabout 700 F. may be used.

The amount of ldiluen tutili iedis naturally dependent" upon the viscosity of the particular base and the viscosity 'of"th'e"pa'rtici1lar diluent and the viscosity desired for the blend. ln thepreparation of cut back asphalts, inge'n'e'rfa'l the'fi'n'al blend will contain from about 5 volume'percent to as much as 60 volume percent of the diluent. v 7

about 'l50volunies of diluent will be used per vol- Iheniethod'pfthis mpa r is described in'detail in co'r'inetion with, the annexed figureswhichset outone hav'iiig'the 'chaiacteristics or the final blend is suitable for 'fourth'fedition. The method herein-is applicable 'thatithe"viscosity"of t h basefie the above- "1t Seeonds'FurjoILj When preparing-cut back as-j petroleum tresiduums or asphalts for example,,rnay bea virgin or cracked heavyjnaphtha,

thefdilu'ent may be a kerosene or alight gas oil,"

Or; in other words, from about 5 volumes to 1 1 shows a side view of a tank adapted for 1 the preparation of a" cut view of the'interio'r of'the tank" use in this blending technique. Tank 11 is provided with a valved conduit 13 positioned near the top of the tank 11 for the introduction of the high viscosity base. Herein an asphalt is introduced, which asphalt has a softening point ASTM of 110 F., a penetration at 77 F. of 110 and a viscosity at 300 F. SSF of 65 and of 3100 SSF at 184 F.

Positioned at the bottom of the tank is a steam coil 14. Immediately above steam coil 14 is set out a distributor means 16. The distributor means 16 is positioned substantially at the bottom of the tank. In this instance, distributor means 16 is about 18 inches above the bottom of the tank with the steam coil being positioned about 9 inches above the bottom of the tank 11. The distributor means 16 is provided with a multiplicity of orifices 17, etc. These orifices are substantially uniformly spaced relative to each other. Distributor means and its orifices are set out over the horizontal cross-section of tank 11 so that dead spaces are virtually eliminated when the contents of the tank are agitated by the introduction of the diluent. Orifices 17, etc. are positioned on the dis tributor means so that fluid emerging or leaving the orifices is directed upward substantially perpendicularly to the bottom of tank 11, i.e., the orifices are on the upper surface of distributor means 16.

In this embodiment, distributor means 16 is a conventional spider such as is used in introduction of air for the agitation of contents of a tank when using air for the blending of cut back asphalt. In this instance, a sixarmed spider is used. The diameter of the spider is about one-half the diameter of the tank 11. Orifices 17, etc. are spaced uniformly on the arms of the spider 16. The arms radiate from a central manifold 18.

It is to be understood that the invention is not limited to the use of a spider having this number of arms-for example, 3 and 4 arms may be adequateor even to the use of a spider. The distributor means may consist of one or more ring-like tubes positioned concentrically within tank 11, for example, 2 or 3 rings may be positioned about the vertical axis of tank 11 so that fluid emerging from the orifices positioned on the top of the ring-like tubing will produce the necessary agitation. Still another arrangement may be the use of paralleltubing manifolded to a common header to provide the necessary distribution of orifices.

The size of the orifices will be determined in part by the tank, the material to be used, the pump pressure which may be developed by the diluent pump, etc. Usually the orifices will have a diameter between about onequarter and three-quarters inch. It is to be understood that smaller or larger diameters may be used, depending on the circumstances and the invention is not to be limited to this precise range of diameters.

Diluent hydrocarbon is introduced by way of line 21 which is joined to manifold 18. Line 21 is provided with a valve and also a check valve which prevents the gintents of the tank from passing back through line In carrying out blending according to the method of this invention, the asphalt is introduced into the tank 11 by way of line 13 to the desired amount. Diluent 1s then pumped through line 21, manifold 18, distributor means 16, and emerges into the tank through orifices 17 etc. The diluent is introduced at a rate such that the et ting fluid, emerging from the orifices, causes violent agitation of the contents of the tank and rapid intermingling of the diluent and the asphalt. In general, the rate of introduction of diluent is such that the fluid emerging from the orifices will reach to about the top of the body of asphalt within the tank. A particularly suitable rate is such that the streams from said orifices have about ten feet of head above the distributor when the tank does not contain the hydrocarbonaceous material, i.e., is empty. By controlling the rate of diluent addition and meeting the above defined requirements of hydrocarbonaceous material viscosity, it is possible to produce an intermingled diluent-base blend at the end of the diluent introduction period, which blend is substantially completely intermingled. By the term substantially completely intermingled it is understood that samples taken from various portions of the tank will have substantially the same viscosity.

In some cases, either due to impracticality of controlling the addition rate, or the need for using a very small amount of diluent with respect to a particular asphalt, substantially uniform intermingling is not obtainable during the time that the diluent is being added. Or, for some reason, it may be desirable to add the diluent at such a rate that free diluent appears above the asphalt layer in the tank resulting in a two-layer situation of diluent and particularly blended asphalt. When this occurs, it is possible to rapidly produce a uniform blend by circulating the contents of the tank by way of line 26, pump 27 and valve line 28 back through line 21, manifold 18, distributor means 16, and orifices 17, etc. Thus the invention is usable not only for obtaining rapid intermingling of a diluent and a very viscous material without circulation of the tank contents through an externalsystem, but is also useful for obtaining complete intermingling of a tank which contains material having non-uniform viscosity due to improper blending or other operational difiiculties. For example, for some reason it may be desirable to introduce material through line 13, both with respect to the asphalt and with respect to the diluent, thus temporarily forming a two-layer condition. Then the contents of the tank will be agitated by circulation through lines 26, 28 and 21. It is necessary when doing this that line 26 draw on diluent material in order to start the blending operation.

The effectiveness of the blending method of this invention is illustrated by the following working examples. It is to be understood that these working examples are merely typical and do not limit the scope of the claimed invention.

Test 1 This test was carried out in a cone-roof tank. The tank was 20 feet internal diameter and had a straight height of 30 feet. Steam coils were positioned about one foot above the bottom. An X-shaped spider was positioned just above the air coils. The diameter of the spider was 6 feet. The spider was provided with orifices ranging from one-quarter to one-half inch in diameter and spaced about six inches apart. The tank was provided with thermocouples at various points and sample points were provided to permit removal of material at various points in the tank. It was found in the tests that temperature gradient in the tank was an excellent measure of the degree of mixing of the hot base and the diluent.

The base used in this test had a softening point of 111 F., a penetration at 77 F. of 110 and had an SSF viscosity of 3100 at 184 F. The diluent was a gas oil derived from catalytic cracking operation. The diluent had a 28 API gravity, an ASTM boiling range of 350 F. to 620 F., and a Saybolt Universal viscosity of 34 seconds at F.

17,550 gallons of the base at a temperature of 243 F. were pumped into the tank; this represents 7.5 feet of tank height. 12,300 gallons of the diluent at about 70 F, were pumped into the tank through the spider over a period of 75 minutes. This represents a rate of 164 gallons per minute. At the end of the diluent delivery, the temperature of the contents of the tank was 164 F. and the S.S.F. viscosity at 77 F. was 124.

In order to check on the uniformity of the mixture in the tank, air was introduced through the distributor for 30 minutes in the normal type of blending operation. At the end of this time, a sample of material was taken from the tank and its S.S.F. viscosity at 77 F. was 125. This shows that at the completion of the diluent injection ibhhj tfii through the distributor orifices-the contentsfof th e tank were uniformly mixed T est 2 In this test, the same tank as used in Test 1 was utilized. 17,250 gallons' of the base us'edin Test 1 was pumped into the tank at a temperature of 255 F. The diluent in anamount of 12,750 gallons was introduced throughthe distributor orifices at 70 F. over a period of 87 minutes; thiswas at a rateof 147 gallons per minute. At thecompletion-of the diluent introduction the temperature distribution in 'the tank was uniform at 173 F. A sample of the tankcontents had an S.S .F. viscosity at 77 F. of 192.1 Tliecontents of the tank werethen circulated by means of a gear pump at a rate of 15,000 gallons per minute for 4 hours. At the end of the circulation, a sample of the tank had an S.S.F. viscosity at 77 F. of 196. This shows that the contents of the tank were uniformly intermingled at the completion of the diluent introduction through the orifices.

Test 3 In this test, 24,700 gallons of the base used in Test 1 were introduced into the same tank as used in Test 1. In order to determine mixing on a lower diluent content blend, only 4,780 gallons of the diluent of Test 1 were added through the distributor orifices. The diluent was added at a rate of 120 gallons per minute over a period of 40 minutes. At the end of the diluent distribution, the temperature distribution in the tank was uniform at 200 F. The viscosity of the blend was 559 S.S.F. at 140 F. Circulation of the tank contents for 3 hours with the gear pump as described in Test 2 did not significantly change the viscosity of the contents.

Test 4 In this test, the conventional procedure was used to mix a blend in the tank of the previous three tests. 23,400 gallons of the base was introduced into the tank at 211 F. 6,450 gallons of the diluent at 70 F. were introduced into the tank through an ordinary line. The contents of the tank were then circulated at 15,000 gallons per minute through a gear pump for 23 hours. The temperature distribution throughout the tank indicated that uniformity of mix had not yet been attained. At this time the viscosity of a sample drawn from the normal discharge line was 444 S.S.F. at 140 F.

At this time air was introduced through the distributor and continued for 15 minutes. After the air blow, temperature distribution indicated that the contents of the tank were now substantially completely mixed and the viscosity of a sample of the blend was 35.1 S. S.F. at 14 F! Test 5 In this test, 143,000 gallons of the base utilized in the previous test was introduced into a tank having a 40 foot internal diameter. This tank was provided with an internal distributor having an X-shape of about 12 feet in diameter, similar in construction to that utilized in Tests 1 through 3. The base had a temperature of 184 F. at the start of the operation. Over a period of 5 /2 hours, at a rate of 76 gallons per minute, 25,000 gallons of the diluent utilized in the previous test was introduced into the tank. The viscosity showed that at the completion of the diluent introduction time the contents of the tank were uniformly mixed. The S.S.F. viscosity of the final blend at 140 F. was 1017.

The above tests show that the procedure of the instant invention is beyond comparison better than the pump circulation method of blending of cut back asphalts and is as eflective, when considering the time needed to introduce the diluent into the tank, as is the conventional procedure of air blowing after the introduction of the asphalt and the diluent, and completely avoids the fire and explosion hazard of the presence of free oxygen at these elevated temperatures.

Thus havin'g'described th'einventi'on, what is cl'aimetl' sf 1. In the method of preparing a'cutback' asphalt from a 'm'aterial selected from the class consisting of semi-solid and solid hydrocarbonaceous materials and a low vis cosity hydrocarbon oil which method utilizes a tank provid'ed with distributor means positioned substantially'at thebottom of said tank, said distributor means being provided with a multiplicity of substantially uniformly spaced orifices, said orifices being betw'een about A and /1 inch in diameter and being positioned so that fluid leavingsaid orifices'is directed upwardly in-a direction, substantially perpendicular to' the bottom of saidtank, said orifices beingordinarily'utilized for the introduction of gaseous fluid to aiford agitation of' the contents of said tank to produce the cutback asphalt, the improvement which comprises introducing said hydrocarbonaceous materials into said tank, maintaining said materials at a temperature between about F. and about 350 to afford a Saybolt Furol viscosity of not more than about 3000 seconds, and introducing said low viscosity hydrocarbon oil through said distributor means at a rate causing violent agitation of the contents of said tank such that by the time all of said hydrocarbon oil has been introduced into said tank the entire contents of said tank are substantially completely intermingled to form the cutback asphalt.

2. In the method of preparing a cutback asphalt from a material selected from the class consisting of semi-solid and solid hydrocarbonaceous materials and a low viscosity hydrocarbon oil which method utilizes a tank provided with distributor means positioned substantially at the bottom of said tank, said distributor means being provided With a multiplicity of substantially uniformly spaced orifices, said orifices being between about A and inch in diameter and being positioned so that fluid leaving said orifices is directed upwardly in a direction, substantially perpendicular to the bottom of said tank, said orifices being ordinarily utilized for the introduction of gaseous fluid to aflord agitation of the contents of said tank to produce the cutback asphalt, the improvement which comprises introducing said hydrocarbonaceous materials into said tank, maintaining said materials at a temperature between about 150 F. and about 350 to aflord a Saybolt Furol viscosity of not more than about 3000 seconds, and introducing said low viscosity hydrocarbon oil through said distributor means at a rate such that substantial uniformity of viscosity of contents of such tank is not attained during the entry of said oil and circulating the contents of said tank through said distributor means by way of said orifices until the viscosity of the contents of said tank has become substantially uniform.

3. The process of claim 1 wherein said hydrocarbona ceous materials are selected from the class consisting of residual oil, resdiual asphalt, cracked tar, blown asphalt, native asphalt and asphaltite,

4. The method of claim 1 wherein said low viscosity hydrocarbon oil is a petroleum oil boiling within the range of about 250 F. and 700 F.

5. The method of blending a low viscosity hydrocarbon oil diluent with a material selected from the class consisting of semi-solid and solid hydrocarbonaceous materials to obtain a cutback asphalt, which method consists essentially of forming a body of said material in a blend ing Zone, maintaining said body at a temperature between about 150 F. and about 350 F. to afford a Saybolt Furol viscosity of not more than about 3000 seconds, and introducing said diluent into said zone in the form of a multiplicity of jet-streams directed substantially perpendicularly upward into said body, at a rate causing violent agitation of the contents of said zone, such that a substantially completely intermingled blend of said material and said diluent is obtained when all of said diluent has been introduced int-o said zone.

6. The method of blending a low viscosity hydrocarbon oil diluent with a material selected from the class con- 7 sisting of semi-solid and solid hydrocarbonaceous materials to obtain a cutback asphalt, which method consists essentially of forming a body of said material in a blending zone, maintaining said body at a temperature between about 150 F. and about 350 F. to afiford a Saybolt Furol viscosity of not more than about 3000 seconds, and introducing said diluent into said zone in the form of a multiplicity of jet-streams directed substantially perpendicularly upward into said body, at a rate causing agitation of the contents of said zone, such that a substantially complete intermingling of said material and said diluent has not been obtained when all of said diluent has been introduced into said zone, and thereafter circulating the contents of said zone in the form of aforesaid jet-streams until a substantially completely intermingled blend of said material and said diluent has been obtained.

References Cited in the file of this patent UNITED STATES PATENTS 1,405,234 Lessing Ian. 31, 1922 2,025,709 Baskin Dec. 31, 1935 2,029,504 Ragatz Feb. 4, 1936 2,058,913 Robinson Oct. 27, 1936 2,069,927 Rhodes et al Feb. 9, 1937 2,069,929 Swanberg Feb. 9, 1937 2,559,518 Smith July 3, 1951 2,711,750 Norcross June 28, 1955 

1. IN THE METHOD OF PREPARING A CUTBACK ASPHALT FROM A MATERIAL SELECTED FROM THE CLASS CONSISTING OF SEMI-SOLID AND SOLID HYDROCARBONACEOUS MATERIALS AND A LOW VISCOSITY HYDROCARBON OIL WHICH METHOD UTILIZES A TANK PROVIDED WITH DISTRIBUTOR MEANS POSITIONED SUBSTANTIALLY AT THE BOTTOM OF SAID TANK, SAID DISTRIBUTOR MEANS BEING PROVIDED WITH A MULTIPLICITY OF SUBSTANTIALLY UNIFORMLY SPACED ORIFICES, SAID ORIFICES BEING BETWEEN ABOUT 1/4 AND 3/4 INCH IN DIAMETER AND BEING POSITIONED SO THAT FLUID LEAVING SAID ORIFICES IS DIRECTED UPWARDLY IN A DIRECTION, SUBSTANTIALLY PERPENDICULAR TO THE BOTTOM OF SAID TANK, SAID ORIFICES BEING ORDINARILY UTILIZED FOR THE INTRODUCTION OF GASEOUS FLUID TO AFFORD AGITATION OF THE CONTENTS OF SAID TANK TO PRODUCE THE CUTBACK ASPHALT, THE IMPROVEMENT WHICH COMPRISES INTRODUCING SAID HYDROCARBONACEOUS MATERIALS INTO SAID TANK, MAINTAINING SAID MATERIALS AT A TEMPERATURE BETWEEN ABOUT 150*F. AND ABOUT 350* TO AFFORD A SAYBOLT FUROL VISCOSITY OF NOT MORE THAN ABOUT 3000 SECONDS, AND INTRODUCING SAID LOW VISCOSITY HYDROCARBON OIL THROUGH SAID DISTRIBUTOR MEANS AT A RATE CAUSING VIOLENT AGITATION OF THE CONTENTS OF SAID TANK SUCH THAT BY THE TIME ALL OF SAID HYDROCARBON OIL HAS BEEN INTRODUCED INTO SAID TANK THE ENTIRE CONTENTS OF SAID TANK ARE SUBSTANTIALLY COMPLETELY INTERMINGLED TO FORM THE CUTBACK ASPHALT. 